Simulating a basal performance bike brake rotor and attached to the watch case with 12 small screws making the hours, this 3-hand with date bike rotor watch is a real bike enthusiast's timepiece. The dial face is made of carbon fiber. It is water-resistant and the quartz movement comes with one-year warranty. The watch band is made of non-allergenic material which is also waterprooft. Diameter: 4cm.Battery Size:SR621SW